辣蓼对大肠埃希菌性腹泻小鼠肠黏膜的修复作用

Effect of Polygoni Hydropiperis Herba on Intestinal Mucosal Repair in Diarrhea Mice Induced by Escherichia coli

目的：研究辣蓼对大肠埃希菌性腹泻小鼠的干预作用,并探讨其可能的作用机制。方法：选取160只昆明种小鼠随机分为正常组,模型组,小檗碱组,辣蓼低、中、高剂量组。除正常组外,其余各组采用腹腔注射致病性大肠埃希菌建立小鼠腹泻模型。辣蓼低、中、高剂量组分别灌胃2.5,5,7.5 g·kg-1辣蓼水提液,小檗碱组给予盐酸小檗碱0.025 g·kg-1,正常组及模型组以等体积生理盐水,每天给药2次。分别于成模后的第1,2,4,6天各组随机抽取5只动物,取十二指肠,光镜下观察病理形态学变化;采用酶联免疫吸附法（ELISA）测定肠组织中炎症因子白细胞介素-1β（interleukin-1β,IL-1β）和肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）的水平;实时荧光定量聚合酶链式反应（Real-time PCR）检测肠组织中转化生长因子-β1（transforming growth factor-β1,TGF-β1）,表皮生长因子受体（epidermal growth factor receptor,EGFR）,Smad3及Smad7 mRNA表达水平。结果：病理学观察发现辣蓼干预后可以明显减轻腹泻小鼠十二指肠黏膜损伤;ELISA结果表明,与正常组比较,模型组小鼠肠黏膜TNF-α和IL-1β的含量明显增多（P〈0.01）;与模型组比较,辣蓼中、高剂量组能降低小鼠肠黏膜TNF-α和IL-1β的含量（P〈0.05,P〈0.01）。Real-time PCR结果表明,与正常组比较,模型组TGF-β1,EGFR表达量均明显升高（P〈0.05,P〈0.01）,Smad7 mRNA表达量明显降低（P〈0.05,P〈0.01）,药物干预后,与模型组比较,各给药组可不同程度调节肠组织中TGF-β1,EGFR,Smad3及Smad7 mRNA表达量（P〈0.05）,且呈现一定的剂量依赖关系。结论：辣蓼对大肠埃希菌性腹泻有良好的治疗作用,其作用机制可能与减少肠组织炎症因子释放、改善肠道黏膜屏障、干预TGF-β/Smads信号转导有关。

Objective： To study the effect of Polygoni Hydropiperis Herba on diarrhea mice induced by Escherichia coli,in order to explore its possible mechanism. Method： A total of 160 KM mice were randomly divided into blank group,model group,berberine group and drug groups（high-dose,medium-dose and low-dose Polygoni Hydropiperis Herba）. All of the other groups,except for the blank group,were injected intraperitoneally with E. coli. The blank group and the model group were given normal saline intragastrically,drug groups were administrated with Polygoni Hydropiperis Herba extract at the dose of 2. 5,5,7. 5 g·kg-1 respectively,and the berberine group was given 0. 025 g·kg-1 of berberine. On the 1 st,2 nd,4 thand 6 thdays after intraperitoneal injection with E. coli,5 mice were randomly selected from each group. Their duodenum histopathological features were observed under optical microscope. The content of interleukin-1β（IL-1β） and tumor necrosis factor-α（TNF-α） was determined by enzyme linked immunosorbent assay（ELISA）,the mRNA expression levels of transforming growth factor-β1（TGF-β1）,and epidermal growth factor receptor（EGFR） Smad3 and Smad7 were detected by real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）. Result： The duodenal intestinal mucosal injury in mice could be significantly alleviated by Polygoni Hydropiperis Herba. ELISA results showed that the content of TNF-α and IL-1β in the model group significantly increased compared with the blank group（P〈0. 01）. The content of TNF-α and IL-1β in the Polygoni Hydropiperis Herba groups（at dose of 5 and7. 5 g·kg-1） was reduced obviously compared with the model group（P〈0. 05,P〈0. 01）. Real-time PCR results showed that the mRNA expressions of TGF-β1,EGFR in the model group significantly increased（P〈0. 05,P〈0. 01）,and mRNA expression of Smad7 in the model group was significantly reduced（P〈0. 01） compared with the bland group. After administration,Polygoni Hydropiperis Herba and berberine can regulate mRNA expressions of TGF-β1,EGFR,Smad3 and Smad7 in duodenum of diarrhea mice（P〈0. 05）,in a dose-dependent manner.Conclusion： Extract of Polygoni Hydropiperis Herba has an obvious effect on diarrhea mice induced by E. coli,and the mechanism may be related to reducing the release of intestinal inflammatory cytokines,alleviating the intestinal mucosal barrier,and intervening TGF-β/Smads signal pathway.